1. Technical Field of the Invention
The present invention generally relates to the field of high intensity lighting devices for use in photography and other purposes. More particularly, the invention relates to a consistent, stable, and high intensity oblong light source, and the method for creating the same.
2. Description of the Related Art
Controllable, high intensity oblong light is applied in many fields, especially in the field of photography. The photography involved in image processing and image inspection mostly requires controllable high intensity oblong lights. For example, the present invention can be used for line-scan camera photography.
Unstable or low intensity lights usually result in photographed images of inferior quality with poor contrast, stability and repeatability. Thus, the intensity, consistency, and stability of the light should be maintained at a high level to insure high image quality. The prior art method of obtaining uniform light-intensity is by manually adjusting the electric current/voltage supplied to the line-light source. However, changing properties occurring in the lighting device such as the heating up of the light bulb, the variance in the output of the power supply, the aging of the line-light source, and other such factors would result in altered light-intensity output given a constant power input.
In photography, images are taken under varying conditions. In order to select proper light-intensity for the particular photograph, light-intensity must be adjusted instantaneously during auto photography, but the current light fittings on the market cannot offer the function of adjusting light intensity instantaneously.
The image acquisition and image inspection industries commonly use line scan photography, which always requires stable, high-intensity, convergent oblong light. Also, for optimized image processing and image inspection of the photographed images, the inspected materials are required to be clear and the images of the non-inspected materials should not to be taken. The parallel or convergence oblong light is the best solution since it may set to illuminate only the desired objects. Lately, LEDs have been used to obtain a high-intensity oblong line-light source for photography, but these line-light sources are low in light-intensity and cannot obtain images from longer distances.
Currently, there is no existing art or technology capable of generating an oblong LED line-light source with a range of 50 mm-500 mm (the distance between the inspected objects to the light). And generally, the line-light source equipment is borrowed from photographing equipment of other applications or is simply refitted equipment. Due to poor lighting equipment, the photography process is not optimal. For example, the use of LEDs as the oblong line-light source can only be implemented at close range (within 50 mm-100 mm). If general lamps or iodine-tungsten lamps with an open ended light width adjustor are used as a line-light source, then the shape of the emitted light would not be controlled and the intensity of the light would be unstable.
What is desired is a method for creating a uniform beam of high intensity oblong light which quickly reaches and maintains a selectable preset light intensity.